Pulsation Dampeners Flow Smoothness Requirements
Below are generally accepted levels of residual fluctuation percentage allowed, to protect against the average level of the problems listed.
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Pipe Shake, Fatigue, Weld Cracking, & Over Stress Unions, Flanges, & Fittings.
Stop pump parts damage.
Gear tooth wear, chatter, and fracture. Drive belt slip, burn-out, and break up. Cross-head, rod, and yoke deflection.
Keep pressure variation less than 12%.
Stop weepage.
Releif valve weeping, surges causing premature lift, fatigue cracking of burst discs.
Keep pressure variation less than 9%.
Stop gauge damage.
Gauges don't read pulsation. Springy bourdon tube, rack and pinnion wag at their own natural frequency, without vibrations you read average steady state pressure.
Keep pressure variation less than 6%.
Incomplete atomization
Stop globlets, drops and squirts when you want a fine spray.
Keep pressure variation less than 5%.
Improve static mixing.
Keep pressure variation less than 4%.
Make mag meters usable.
Keep flow-fluctuations less than 3%.
Stop paddle wheel meter surging.
Keep pressure variation less than 2%.
Turbine screw meter "racheting".
Kick from pulse starts the spin, weight of screw blades and shaft keeps it spinning, next kick gives overspeed or stops it. Soon you have no accuracy.
Stay less than 1.5% depending on viscosity.
Coriolis
Loop tube 90Hz or straight tube 900 Hz. Hit a multiple or divisor of, or that frequency, and the tubes swing wildly. They can register 100 Kilos/sec when you only have 5.
Stabilize to less than 1.0%.
No non-sense vortex shedding.
Vortexexs are minute low pressure zones and are created at a rate relative to flow velocity. Without pressure pulsation "vortex shedding" meters work.
Go less than 0.75%.
